[mutter] clutter: Enable negative offsets in delete surrounding text

[Carlos Garnacho <carlosg src gnome org>]

commit 2cfdbbd7305ff0bf06064538533b598292758c81
Author: Takao Fujiwara <tfujiwar redhat com>
Date:   Thu Aug 15 18:47:03 2019 +0900

    clutter: Enable negative offsets in delete surrounding text
    
    The input method can assign a negative value to
    clutter_input_method_delete_surrounding() to move the cursor to the left.
    But Wayland protocol accepts positive values in delete_surrounding() and
    GTK converts the values to the negative ones in
    text_input_delete_surrounding_text_apply().
    
    https://gitlab.gnome.org/GNOME/mutter/issues/539

 clutter/clutter/clutter-input-focus-private.h |  2 +-
 clutter/clutter/clutter-input-focus.c         |  2 +-
 clutter/clutter/clutter-input-focus.h         |  2 +-
 clutter/clutter/clutter-input-method.c        |  4 ++--
 clutter/clutter/clutter-input-method.h        |  2 +-
 clutter/clutter/clutter-text.c                | 14 ++++++++++++--
 src/wayland/meta-wayland-text-input-legacy.c  | 10 ++++++++--
 src/wayland/meta-wayland-text-input.c         | 10 ++++++++--
 8 files changed, 34 insertions(+), 12 deletions(-)
---
diff --git a/clutter/clutter/clutter-input-focus-private.h b/clutter/clutter/clutter-input-focus-private.h
index 563e58978..ccde45d0e 100644
--- a/clutter/clutter/clutter-input-focus-private.h
+++ b/clutter/clutter/clutter-input-focus-private.h
@@ -29,7 +29,7 @@ void clutter_input_focus_focus_out (ClutterInputFocus  *focus);
 void clutter_input_focus_commit (ClutterInputFocus *focus,
                                  const gchar       *text);
 void clutter_input_focus_delete_surrounding (ClutterInputFocus *focus,
-                                             guint              offset,
+                                             int                offset,
                                              guint              len);
 void clutter_input_focus_request_surrounding (ClutterInputFocus *focus);
 
diff --git a/clutter/clutter/clutter-input-focus.c b/clutter/clutter/clutter-input-focus.c
index 7a004f259..ece1fa59a 100644
--- a/clutter/clutter/clutter-input-focus.c
+++ b/clutter/clutter/clutter-input-focus.c
@@ -217,7 +217,7 @@ clutter_input_focus_commit (ClutterInputFocus *focus,
 
 void
 clutter_input_focus_delete_surrounding (ClutterInputFocus *focus,
-                                        guint              offset,
+                                        int                offset,
                                         guint              len)
 {
   g_return_if_fail (CLUTTER_IS_INPUT_FOCUS (focus));
diff --git a/clutter/clutter/clutter-input-focus.h b/clutter/clutter/clutter-input-focus.h
index 65736a799..008883af6 100644
--- a/clutter/clutter/clutter-input-focus.h
+++ b/clutter/clutter/clutter-input-focus.h
@@ -41,7 +41,7 @@ struct _ClutterInputFocusClass
 
   void (* request_surrounding) (ClutterInputFocus *focus);
   void (* delete_surrounding)  (ClutterInputFocus *focus,
-                                guint              offset,
+                                int                offset,
                                 guint              len);
   void (* commit_text) (ClutterInputFocus *focus,
                         const gchar       *text);
diff --git a/clutter/clutter/clutter-input-method.c b/clutter/clutter/clutter-input-method.c
index 4bf1b0ec8..031b103df 100644
--- a/clutter/clutter/clutter-input-method.c
+++ b/clutter/clutter/clutter-input-method.c
@@ -168,7 +168,7 @@ clutter_input_method_class_init (ClutterInputMethodClass *klass)
                   G_TYPE_FROM_CLASS (object_class),
                   G_SIGNAL_RUN_LAST,
                   0, NULL, NULL, NULL,
-                  G_TYPE_NONE, 2, G_TYPE_UINT, G_TYPE_UINT);
+                  G_TYPE_NONE, 2, G_TYPE_INT, G_TYPE_UINT);
   signals[REQUEST_SURROUNDING] =
     g_signal_new ("request-surrounding",
                   G_TYPE_FROM_CLASS (object_class),
@@ -292,7 +292,7 @@ clutter_input_method_commit (ClutterInputMethod *im,
 
 void
 clutter_input_method_delete_surrounding (ClutterInputMethod *im,
-                                         guint               offset,
+                                         int                 offset,
                                          guint               len)
 {
   ClutterInputMethodPrivate *priv;
diff --git a/clutter/clutter/clutter-input-method.h b/clutter/clutter/clutter-input-method.h
index 92f960f0a..b7f9a474e 100644
--- a/clutter/clutter/clutter-input-method.h
+++ b/clutter/clutter/clutter-input-method.h
@@ -68,7 +68,7 @@ void clutter_input_method_commit (ClutterInputMethod *im,
                                   const gchar        *text);
 CLUTTER_EXPORT
 void clutter_input_method_delete_surrounding (ClutterInputMethod *im,
-                                              guint               offset,
+                                              int                 offset,
                                               guint               len);
 CLUTTER_EXPORT
 void clutter_input_method_request_surrounding (ClutterInputMethod *im);
diff --git a/clutter/clutter/clutter-text.c b/clutter/clutter/clutter-text.c
index 8efbfa07c..e1947c437 100644
--- a/clutter/clutter/clutter-text.c
+++ b/clutter/clutter/clutter-text.c
@@ -348,13 +348,23 @@ clutter_text_input_focus_request_surrounding (ClutterInputFocus *focus)
 
 static void
 clutter_text_input_focus_delete_surrounding (ClutterInputFocus *focus,
-                                             guint              offset,
+                                             int                offset,
                                              guint              len)
 {
   ClutterText *clutter_text = CLUTTER_TEXT_INPUT_FOCUS (focus)->text;
+  int cursor;
+  int start;
 
+  cursor = clutter_text_get_cursor_position (clutter_text);
+  start = cursor + offset;
+  if (start < 0)
+    {
+      g_warning ("The offset '%d' of deleting surrounding is larger than the cursor pos '%d'",
+                 offset, cursor);
+      return;
+    }
   if (clutter_text_get_editable (clutter_text))
-    clutter_text_delete_text (clutter_text, offset, len);
+    clutter_text_delete_text (clutter_text, start, len);
 }
 
 static void
diff --git a/src/wayland/meta-wayland-text-input-legacy.c b/src/wayland/meta-wayland-text-input-legacy.c
index 3ad48988a..3b5624c36 100644
--- a/src/wayland/meta-wayland-text-input-legacy.c
+++ b/src/wayland/meta-wayland-text-input-legacy.c
@@ -94,17 +94,23 @@ meta_wayland_text_input_focus_request_surrounding (ClutterInputFocus *focus)
 
 static void
 meta_wayland_text_input_focus_delete_surrounding (ClutterInputFocus *focus,
-                                                  guint              cursor,
+                                                  int                offset,
                                                   guint              len)
 {
   MetaWaylandGtkTextInput *text_input;
+  uint32_t before_length;
+  uint32_t after_length;
   struct wl_resource *resource;
 
   text_input = META_WAYLAND_GTK_TEXT_INPUT_FOCUS (focus)->text_input;
+  before_length = offset <= 0 ? -offset : offset;
+  after_length = len >= before_length ? (len - before_length) : len + before_length;
 
   wl_resource_for_each (resource, &text_input->focus_resource_list)
     {
-      gtk_text_input_send_delete_surrounding_text (resource, cursor, len);
+      gtk_text_input_send_delete_surrounding_text (resource,
+                                                   before_length,
+                                                   after_length);
     }
 }
 
diff --git a/src/wayland/meta-wayland-text-input.c b/src/wayland/meta-wayland-text-input.c
index 4e7d18b25..13a9741c7 100644
--- a/src/wayland/meta-wayland-text-input.c
+++ b/src/wayland/meta-wayland-text-input.c
@@ -166,17 +166,23 @@ meta_wayland_text_input_focus_defer_done (ClutterInputFocus *focus)
 
 static void
 meta_wayland_text_input_focus_delete_surrounding (ClutterInputFocus *focus,
-                                                  guint              cursor,
+                                                  int                offset,
                                                   guint              len)
 {
   MetaWaylandTextInput *text_input;
+  uint32_t before_length;
+  uint32_t after_length;
   struct wl_resource *resource;
 
   text_input = META_WAYLAND_TEXT_INPUT_FOCUS (focus)->text_input;
+  before_length = offset <= 0 ? -offset : offset;
+  after_length = len >= before_length ? (len - before_length) : len + before_length;
 
   wl_resource_for_each (resource, &text_input->focus_resource_list)
     {
-      zwp_text_input_v3_send_delete_surrounding_text (resource, cursor, len);
+      zwp_text_input_v3_send_delete_surrounding_text (resource,
+                                                      before_length,
+                                                      after_length);
     }
 
   meta_wayland_text_input_focus_defer_done (focus);